1. Field of the Invention
The present invention relates to a light-shielding mechanism for preventing a sheet-like member from being irradiated with unwanted extraneous light while the sheet-like member is being fed and processed in a sheet-like member processing apparatus.
2. Description of the Related Art
There is known a system for recording radiation image information of a subject such as a human body with a stimulable phosphor, and reproducing the recorded radiation image information on a photosensitive medium such as a photographic film, or displaying the recorded radiation image information on a display device such as a CRT or the like.
When a radiation energy such as X-rays, xcex1-rays, xcex3-rays, electron beams, ultraviolet radiation, or the like is applied to a certain phosphor, it stores part of the applied radiation energy. When stimulating light such as visible light is subsequently applied to the phosphor, the phosphor emits light depending the stored radiation energy. Such a phosphor is referred to as a stimulable phosphor. A stimulable phosphor is usually used in the form of a sheet which is referred to as a stimulable phosphor sheet (sheet-like member).
The above known system includes an image information reading apparatus (sheet-like member processing apparatus) which comprises a reading unit (scanning unit) for reading image information recorded on a stimulable phosphor sheet, and an erasing unit for erasing remaining image information from the stimulable phosphor sheet after the recorded image information has been read. In the image information reading apparatus, a cassette housing a stimulable phosphor sheet which bears radiation image information of a subject recorded by an external exposure device is inserted into a loading unit, or a plurality of such cassettes are inserted into respective loading units.
Thereafter, the lid of the cassette is opened, and then the stimulable phosphor sheet is taken out of the cassette by a sheet feeding mechanism. The stimulable phosphor sheet is delivered to the reading unit by a sheet delivering mechanism. In the reading unit, the recorded image information is read from the stimulable phosphor sheet, and then remaining image information is erased from the stimulable phosphor sheet in the erasing unit, after which the stimulable phosphor sheet is placed into the cassette which has been disposed in the loading unit.
The above system also includes an image information reproducing apparatus (sheet-like member processing apparatus) for reproducing radiation image information on a photographic photosensitive medium such as a photographic film or the like. In the image information reproducing apparatus, a magazine contains a plurality of photographic photosensitive mediums, and one of the photographic photosensitive mediums at a time is removed from the magazine and delivered by a suction mechanism to a sheet feeding mechanism (sheet feeder), which feeds the photographic photosensitive medium to a recording unit (scanning unit). In the recording unit, the radiation image information obtained from the stimulable phosphor sheet is recorded on the photographic photosensitive medium by the application of a laser beam or the like.
In the image information reading apparatus and the image information reproducing apparatus, in order to allow the reading unit and the recording unit to read and record high-quality images highly accurately, the stimulable phosphor sheet and the photographic film (hereinafter collectively referred to as a xe2x80x9csheet-like memberxe2x80x9d) fed in the apparatus need to be reliably shielded from unwanted light (extraneous light).
It has been customary to employ full-width rubber rollers having an axial length equal to or greater than the width of sheet-like members and a labyrinth structure for shielding the feed path from extraneous light in the apparatus. However, the conventional light-shielding arrangements are expensive to manufacture and complex in structure, making the apparatus considerably large in size.
It is a primary object of the present invention to provide a light-shielding mechanism of simple and inexpensive structure for shielding a sheet-like member from unwanted extraneous light in a sheet-like member processing apparatus.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.